"Tools for optimizing prompts" matching MCP servers:

MCP server for deterministic financial transactions, providing tools to fetch account balances, check blocked PIX keys, and execute atomic PIX transfers with integer-cent precision.

Checks live x402 routes across Base, Solana, and Algorand before agents spend. $0.003 USDC settles only for a valid live eligible route; normal typed misses are not settled. Free preview and validate tools. Seller payment is separate; the agent keeps its wallet. Optional signed route-binding receipts support buyer-side checks.

Enables AI agents to call paid APIs and settle HTTP 402 payment challenges with USDC on Base, without private keys ever being involved.

Pay-per-call USDC payment proxy for AI agents. Issue scoped Pay Tokens with hard spending caps and auto-journal every charge to freee / Money Forward / QuickBooks.

An MCP server that wraps the Check Payroll API, providing 263 tools for managing companies, employees, contractors, payrolls, tax configuration, and more.

MCP server that gates API calls to AI agents using proof-of-work (free) or Lightning payment (3 sats), providing challenge, verify, and status tools for per-call authentication without accounts.

Enables AI coding assistants to log billable hours into the Keeping time-tracking service via MCP tools, with dry-run protection for all write operations.

Enables MCP clients to access Monobank's open API for exchange rates, account and jar balances, and statements, as well as set webhooks, using natural language tools.

Enables AI assistants to build PayRetailers cross-border payment integrations accurately by providing official documentation, endpoint specs, country-specific payload validation, webhook guidance, and integration prompts as MCP resources, tools, and prompts.

MCP server providing Polymarket weather-market bucket-transition signals for AI agents, with free city/signal inspection tools and paid signal bundles via USDC on Base using x402.

Enables running a local MCP server for Poland's KSeF (Krajowy System e-Faktur) e-invoicing system, so invoice data stays on the user's own machine rather than passing through an intermediary service. It currently exposes only a diagnostic server_info tool, with invoice search and retrieval tools still to come.

Enables querying OpenCode Go subscription quota (rolling, weekly, and monthly usage) and Zen prepaid balance as MCP tools.

An MCP server that exposes the pacs008 ISO 20022 FI-to-FI Customer Credit Transfer library as tools for AI agents and assistants, enabling generation, validation, and parsing of pacs.008 credit transfer XML messages.

MCP server for real FDM 3D-printing slicing, quoting, and design-for-manufacturability analysis via the FabTally API, supporting 12 printer profiles and 12 materials. Includes free discovery/printability tools and paid slice/quote/orientation tools settled via x402 (USDC on Base).

MCP server exposing a fictional payment domain as tools, resources, and prompts, enabling reasoning over transactions, payment hubs, services, and system health.

A Model Context Protocol server that enables interaction with Monobank API, providing tools for currency exchange rates, client info, and account statements.

Enables AI agents to manage a fictional B2B workspace SaaS (Tessera) with tools for ticketing, invoicing, customer management, and trial extensions, featuring a human-in-the-loop confirm pattern for safety.

Exposes all 379 Invoice Ninja v5 REST API endpoints through three consolidated tools (list, describe, call), enabling full invoice management and business operations via natural language.

Provides AI agents with SSRF-protected URL intelligence and 32 paid REST/MCP tools, plus a free catalog search, with payments in USDC on Base Mainnet.

Unified gateway for ISO 20022 message families, providing meta-tools to search, describe, validate, generate, and parse financial messages.